For the convex hull algorithm we have to be able to test whether a point r lies left or right of the directed line through two points p and q. Let p = (px, py), q = (qx, qy), and r = (rx, ry).
a) Show that the sign of the determinant
1 pxpy
D= 1qxqy
1 rxry
determines whether r lies left or right of the line.
b) Show that |D| in fact is twice the area of the triangle determined by p, q, and r.
c) Why is this an attractive way to implement the basic test in algorithm CONVEXHULL? Give an argument for both integer and floating point coordinates.

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The answer is d ? ); ))4))

Choice 2.the algorithm constantly checks to see if the value in the position before is greater than the value in the current position. if there is even one instance, it will return false and stop looping.using an if-statement without } and { means that the if-statement true condition only applies for the next lineconsider  . the condition  checks if previous position is greater than or equal to current position. if it is, it will make method return false. for that example, it won't.consider  , it would return falseconsider  . it would return false